Olduvai Gorge

Olduvai Gorge is one of the most prominent paleoanthropological locations in the world, and was designated a UNESCO World Heritage site in 1979. Located in northern Tanzania on the eastern edge of the Serengeti Plain, Olduvai falls within the jurisdiction of the Ngorongoro Conservation Area, which is situated within the greater East African Rift System. Exposed through erosional downcutting by the intermittent Ndutu Stream over the last 500,000 years, Olduvai has one of the most continuous paleoanthropological records in the world, exceptional archaeological site preservation due to the low-energy sedimentary environment, and a timeframe of human evolution that spans the transition from the Oldowan to the Later Stone Age (LSA) to even archaeological remains of modern humans.

Today, the Gorge is nearly 50 kilometers long, with some exposures reaching depths of up to 100 meters. Separated into seven geologic beds (Beds I-IV, Masek, Ndutu, and Naisuisui), the date range for Olduvai extends from about 2 million years ago to today. Although referred to as a ‘site’, a large number of archaeological localities comprise the Olduvai paleoanthropological landscape; in fact, there are over 70 such archaeological localities in Beds I and II alone! The geological deposits over the seven beds represent a range of lakeside and stream channel localities where early human ancestors lived, created stone tools, and butchered carcasses and processed plants for food, all while living in the shadow of the Ngorongoro volcano. This volcano erupted periodically and provided the material for dating the archaeological sites around the Gorge. Early Investigations into Olduvai Gorge German entomologist Wilhelm Kattwinkel was the first European to identify Olduvai Gorge in 1911 when he was collecting butterflies on the Serengeti. Kattwinkel found the initial fossils in the Gorge that would lead to many great discoveries over the next century: those of a prehistoric three-toed horse. German volcanologist and paleontologist Hans Reck led a follow up expedition in 1913 and discovered the first human fossils, subsequently labeled Olduvai Hominid (OH) 1; a partial Homo sapiens skeleton from the upper sequence of the Olduvai Beds. Olduvai is actually a misspelling of Olduwai, the German word for the Gorge, which is a misspelling of Oldupai, the Maasai word for the wild sisal plant (Sansevieria ehrenbergiit) that grows extensively throughout the Gorge.
In 1931, Louis Leakey and Henrietta Wilfrida “Frida” Leakey (née Avern) led the Third East African Archaeological Expedition to Olduvai Gorge. Hans Reck, who had not returned to Olduvai since before World War I, accompanied Louis and Frida on the expedition after discussing his finds with Louis a few years earlier. Soon after their arrival, an Acheulean handaxe was recovered by one of their African

workers, thus proving that Olduvai was a “unique showcase not only of animal fossils, but also of tool forms and associated human occupation sites over a period of a million and a half years or more” (Louis Leakey, 1974). These Acheulean handaxes were the forerunners to the thousands of stone tools that would be excavated in the Gorge over the next 85 years. Leakey would go on to designate one of the richest fossil and stone tool assemblage sites in the Gorge “Frida Leakey Korongo” (FLK); korongo being the Swahili word for “gully.” Coincidently, nearly 30 years later, Leakey’s second wife Mary would find the
remains of Zinjanthropus (Paranthropus boisei – OH 5) at the FLK site.

Why is Olduvai Important?
The discovery of P. boisei in 1959 by Mary Leakey was a defining moment in the history of paleoanthropology, as it was OH 5 that convinced people East Africa was a sensible place to investigate the earliest evidence of human ancestry. Although other hominin ancestors had been found elsewhere prior to the discovery of P. boisei (e.g. Au. africanus, H. erectus, and H. neanderthalensis), it was Louis Leakey’s charismatic personality, his skill in promoting himself and his discoveries, and his ability to acquire funding over four decades that set the stage for the paleoanthropological ‘gold rush’ that would define East Africa’s cradle of humanity.
From the time when Mary Leakey found OH 5 at FLK, over 80 hominins have been discovered; the most recent being OH 86, a manual proximal phalanx from the 1.84 million year old Philip Tobias Korongo (PTK) site. The hominin fossil record at Olduvai includes specimens of P. boisei, H. habilis, H. erectus, and H. sapiens; but it is possible that H. rudolfensis and H. heidelbergensis lived in or around Olduvai, as their fossil material is present in other nearby paleoanthropological sites. Although older assemblages have been subsequently discovered, Olduvai is also the locality for which the Oldowan stone tool industry tradition was first defined. The Oldowan industry consists mostly of small flakes, flaked cobbles, and percussive tools and is associated with the genus Homo throughout East and South Africa. Some of the earliest evidence of the Acheulean is also found at Olduvai, including extremely sophisticated, highly symmetrical and bifacially flaked large cutting tools dated to 1.7 million years old. The Acheulean assemblage is in agreement with those traits traditionally ascribed to the Early Acheulean, particularly with the earliest examples documented in East Africa for a similar chronological range (at Kokiselei 4, West Turkana, Kenya and Konso-Gardula, Ethiopia).

As a clearly defined and self-contained archaeological landscape representing the fossil and stone tool record of the broader East African region, Olduvai Gorge presents an exceptional opportunity to examine the effective human response to such things as fluctuating climates, habitat choice, and diet. Current paleoanthropological research focused on Olduvai is befitting given that the region boasts archaeological remains with extraordinary temporal and spatial evidence for human behaviour. Only at Olduvai Gorge do we see human evolutionary transitions alongside changes in stone tool technologies over a period of 2 million years.